what is happening with kernel development?
ever since forcing hardware specific patches from development-sources into gentoo-dev-sources, the kernel development for sparc platform has stopped dead in its tracks - the latest available kernel is 2.6.7-r14 which is quite old by now.

second question - whats my chance of using development-sources >=2.6.9 sucessfully on sparc platform ? anyone out there ?

I've had development-sources-2.6.9 on my Ultra 5 briefly. It didn't cause any problems I'm aware of, but I went back to a more supported version because it didn't fix the specific problem I was after. (Mouse baudrate autodetect doesn't)

There is an entry in the Changelog for 2.6.10 that looks promising for that fixs, so I'll be trying that soon....

1) Our previous kernel maintainer is no longer able to maintain, so it's taking us a little to switch around

2) development-sources no longer works the way it did up to and including 2.6.7, so we need to switch over to gentoo-dev-sources. One of the problems here is anything greater than 2.6.7 tends to be unstable during periods of high disk I/O, especially on SMP boxes.

what about alternative schedulers to solve the unstability with high disk i/o? and which filesystems are affected? i'm thinking of converting a raid0 array with high disk i/o to reiserfs4 - whats the score on that one on sparc64 platform?

i've used reiserfs3 on number of sparc64 boxes running 2.6.5 and 2.6.7 kernels and never had any problems.
(when i say "using", i don't mean just install and thats it. i have used it on normal disks, on lvm2, on raid0 and never any problems).

my only problems are before mentioned problems which appear on smp platforms.

Reiserfs3 has been hit and miss depending on the person. Some people have good luck w/it and some don't. I don't know that anyone has done any extensive testing with Reiserfs4 on SPARC, so you may be in for a bumpy ride there.

I just recently installed gentoo-dev-sources-2.6.7(because i need more than 32 supplementary groups max) and noticed that system load(~dayly average) is twice higher than under 2.4. Maybe it's just a coincidence... does anybody noticed same thing?

I can echo what cyan said about load vs responsiveness. I have the exact same experience
with 2.6.8.

On the topic of filesystems, i have played with Reiserfs a bit, it gave me a bad feeling of
living on the edge. After having to reinstall the whole system twice, i came back to
good old ext3. I have been running ext3 for much longer now, the only time it gave me
trouble was when i enabled DMA on my WD IDE hard-drive, and i got massive filesystem
corruption in return, so that was my bad.

So yeah, i'd say stick with ext3 for anything more serious then mere curiosity. BTW, i don't
have a SMP box, so YMMV.

I'm not going to switch to 2.6 until SMP is available for the sparcstation 20. As it is currently not and the committed gentoo developers are not reachable i think that my machine is running 2.4 until it dies

I have 2.6.10 running on my SunBlade 100 now, however, it has only been up for a few days. I'll wait to see if it will lock up. I am having no luck running ALSA with it whatsoever at this point, but I have to research it a bit further. But hey, at least I have a 64 bit kernel Linux box (okay okay, so userland is 32 bit).